1. Technical Field
The present invention relates to encoding video, more specifically to encoding frames that are stored in a frame memory.
2. Background Art
HEVC (High Efficiency Video Coding) is an MPEG standard targeted for a compression ratio that is twice of the H.264 compression ratio. With the main technical objective of achieving a very high compression ratio, HEVC is a general purpose video encoding technology that can be used in nearly every transmission medium, such as storage media, internet and satellite broadcasting, and for various video resolutions and can easily compress high-resolution images. As video resolutions have been increasing recently, the markets today require an SoC (System on Chip) that can process Ultra High Definition resolutions.
As picture qualities reach ultra-high resolutions, there are increased frequencies of data communication between an external memory and an internal memory when a video codec is developed using the system semiconductor. Accordingly, the memory bandwidth problem becomes more serious with the increased resolution, deteriorating the performance of the whole system. Studied to solve this problem is a frame coding technology in which coded frames are stored when data is read or written in the external memory in the video codec.
In the conventional technology, the frame memory has been compressed using a lossy compression algorithm if more than a predetermined number of bits are generated during the coding, and a lossless compression algorithm if the generated bits are not more than the predetermined number. This method, however, has the problems of deteriorated picture quality due to the use of the lossy compression algorithm and increased power consumption due to the heavy hardware use because of the implementation using both the lossless compression algorithm and the lossy compression algorithm.